Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

010
FXUS63 KLOT 180621
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
121 AM CDT Thu Jun 18 2026

.KEY MESSAGES...

- Next significant chance of rain is Sunday with potential for
  locally heavy rainfall.

&&

.DISCUSSION...
Issued at 121 AM CDT Thu Jun 18 2026

After a couple of active days, a much quieter weather pattern
expected the next few days. Northwest flow aloft will persist
with high pressure across the Ohio Valley blocking any return
moisture from the Gulf. A couple of subtle/weak perturbations in
the northwest flow will could bring some spotty showers to the
area, mainly Friday night. Coverage is expected to be on the low
side, as is confidence in it raining, so the slight chance to
chance pops offered up by the NBM seem reasonable. Temperatures
the next couple of days will be a bit below average with
comfortable dewpoints generally in the 50s.

For days now, medium range guidance has been in good agreement
in bringing a stronger shortwave trough into the Midwest late in
the weekend. By Saturday, the aforementioned surface ridge is
expected to shift eastward allowing for southerly flow from the
Gulf to advect moisture northward in advance of the next
system. There remains some latitudinal variability and
differences in guidance with respect to the track of the
associated sfc low, but there has been a pretty consistent
signal for a swath of potentially heavy rainfall setting up in
or near our CWA Sunday. Accordingly, NBM pops are quite high
and no changes were needed.

Northwest flow aloft will continue into next week. Drier
weather is expected to start the week in the wake of the Sunday
system. Next chance of showers/storms looks to be toward the
middle of next week. Temperatures next week look to remain near
to slightly below average.

- Izzi

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 1228 AM CDT Thu Jun 18 2026

Forecast concerns include...

Mvfr cigs overnight through mid morning.
Gusty westerly winds through late this morning.

A large area of mvfr cigs across southeast MN and much of WI is
expected to move southeast across the terminals in the predawn
hours and persist through mid/late morning. Have maintained cigs
around 2kft but its possible there will be a few hours of low
mvfr cigs and adjustments may be needed with the 09z update.
Once this mvfr cloud cover shifts southeast of the terminals by
midday, vfr is expected for the rest of the period.

Westerly winds will gust into the mid 20kt range through mid
morning and will then steadily diminish with gusts ending by
early afternoon and speeds diminishing under 10kt with sunset
this evening. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement until 4 AM CDT early this morning for
     ILZ006-ILZ103-ILZ104.

IN...Beach Hazards Statement through this afternoon for INZ002.

LM...Small Craft Advisory until 9 AM CDT this morning for the IL
     and IN nearshore waters.

&&

$$

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